Sorting a Java Array by Parity
The challenge
Given an array A of non-negative integers, return an array consisting of all the even elements of A, followed by all the odd elements of …
Technical Articles
In-depth guides, insights, and best practices for modern software engineering
Remove Duplicates from Sorted Array in Java
Say you have an array of primitive integers and you want to remove all duplicates.
You can find out how many non-duplicate integers are in the array …
Read Article →Replace Elements with Greatest Element on Right Side using Java
The challenge
Given an array arr, replace every element in that array with the greatest element among the elements to its right, and replace the last …
The Valid Mountain Array Problem using Java
Introducing the problem
Given an array A of integers, return true if and only if it is a valid mountain array.
Recall that A is a mountain array if …
Read Article →HashMaps (aka: Dictionaries) in Python
Introduction
Java has a built-in called HashMap. It allows you to store and very quickly retrieve key value pairs.
In Python, this is called a …
Read Article →Find Numbers with Even Number of Digits using Java
The challenge
Given an array nums of integers, return how many of them contain an even number of digits.
Example 1:
Example 2:
Constraints:
1 …
The Relational Database Model
Relational databases first made an appearance in the mid-1970s, between the years 1974 and 1977 with the creation of Ingres and System R which led to …
Read Article →How to use a Java HashSet by example
What is a HashSet
A HashSet is an unordered collection containing unique elements. It has the standard collection operations Add, Remove, Contains, …
Get The Shortest Path in Binary Matrix using Python
The challenge
In an N by N square grid, each cell is either empty (0) or blocked (1).
A clear path from top-left to bottom-right has length k if and …
Palindrome Partitioning in Python
The problem
Given a string s, partition s such that every substring of the partition is a palindrome.
Return all possible palindrome partitioning of s …
Read Article →Faster alternative to MySQL Delete Table Contents / Truncate
From time to time you might have some rather big tables that you want to delete all the data quickly and start afresh.
You have a few options at this …
Read Article →Best Time to Buy and Sell Stock with Python
The problem
Say you have an array prices for which the ith element is the price of a given stock on day i.
Design an algorithm to find the maximum …
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